The invention relates to the fastening of the buckets and possibly also the skim cutters to cutting wheels, such as bucket wheels or under water cutting wheels, wherein the buckets and possibly also the skim cutters are exchangeably attached by way of connecting elements to the outer circumference of the cutting wheels. The buckets and skim cutters will also be generally referred to as digging tool components and the bucket wheels and cutting wheels will also be generally referred to as supporting wheels. The entire rotary structure will also be referred to as digging wheel assembly.
German Unexamined Published Patent Application 3,822,235 discloses a bucket wheel body, particularly for surface mining apparatus, which is composed of a supporting body that is rotatably mounted on the axis of the bucket wheel and is provided with a plurality of buckets that are connected with the carrier body by means of at least one ring carrier. The ring carrier is disk-shaped and, seen in the circumferential direction, is provided with two superposed approximately horizontally extending flanges that are connected with the ring carrier outside of the bucket wheel body. By means of connecting elements, the front and rear regions of the buckets provided at the ring carriers are releasably connected with the bucket wheel body.
German Unexamined Published Patent Application 3,737,893 discloses a bucket wheel bucket which has at its rear a device for preventing the buckets from being loaded with larger chunks of material (rock deflector), with the device being composed like a cage of a plurality of rods extending in the conveying direction of the bucket wheel and being disposed between the back of the preceding bucket and the next following bucket. The buckets as well as the rock deflector are fastened by way of connecting elements so that exchangeability when worn is ensured.
The drawbacks of the prior art are essentially that complicated structures must be provided on the circumference of the bucket wheel so that the buckets can be connected with it by means of the connecting elements. Such connecting elements are often formed by sleeves and pins cooperating therewith which, under certain circumstances, require much mechanical working and may deform if under certain conditions the digging forces are high so that ultimately problems arise again during the removal of the buckets. In the past, it has also been found that the reaction forces generated by the digging forces often caused the connecting elements, on the one hand, and the fastening elements, on the other hand, to break off.